third_party/blink/web_tests/http/tests/canvas/canvas-filter-svg-external-expected.html

<svg style="display: block; width: 0; height: 0">
  <defs>
    <filter id="blur">
      <feGaussianBlur stdDeviation="3 3"/>
    </filter>
  </defs>
</svg>
<canvas id="canvas" width="100" height="100"></canvas>
<script>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.fillStyle = '#0f0';
ctx.fillRect(0, 0, 90, 90);
ctx.filter = 'url(#blur)';
ctx.fillStyle = '#f00';
ctx.fillRect(20, 20, 30, 30);
</script>